The development of parasites on livestock and pets is a well-known worrying problem. It may have major consequences on hygiene and the propagation of certain diseases in the case of livestock rearing, such as: salmonellosis especially in aviculture, enterocolitis, verminosis, mastitis and keratoconjunctivitis in cattle, foot-and-mouth disease, swine fever, erysipelothrix infection and myxomatosis in rabbits. This development may have major consequences on the economic productivity of the livestock business, especially in aviculture, and in particular on the rearing of table chickens, and turkeys, and laying hens.
It is especially known practice to combat parasites using neurotoxic substances and growth inhibitors such as synthetic pyrethroids, organophosphorus compounds or carbamates, for example. These products are applied either by spraying or by thermo-nebulization. Their uses are, for the vast majority of the products, prohibited in the presence of animals. The reason for this is that these substances have the drawback of also being toxic to the animal on which the parasites develop. Some of these substances also have an allergenic nature to man or animals. When the rearing of the animal is intended for human food consumption, the use of neurotoxic parasiticidal agents is prohibited since these substances contaminate the food chain, as stated in the European directives on biocides (98/8 EC) and on plant protection (91/414 EEC). It also presents risks to the breeders.
It is also known that parasiticidal compositions based on natural or synthetic essential oils or on pyrethroids or on organophosphorus compounds used as alternatives to organochlorine compounds have an efficacy that decreases rapidly over time. These parasiticidal compositions have an action that may be termed a “shock action”. Their efficacy is generally of the order of a few days, and at most of the order of a few weeks. This is due to non-zero vapor pressures of the components that give rise to their volatilization over time and moreover to their degradation by oxidation.
Parasites that have been eliminated at one particular moment may reinfest a livestock unit in the course of livestock production. The toxicity of such compositions, including their toxicity to animals, limits their use on occupied buildings.
Patent WO 01/35744 discloses a parasiticidal composition based on silica. This composition in gel form is free of neurotoxic substances, but is expensive. The composition is not a powder but a granular system which solid particles are surrounded by a liquid phase and behaves as a liquid, as it forms a horizontal surface in a recipient. The aerated gel composition, comprising gelling agent and high amount of water, sticks strongly on treated surfaces. This is an interesting property to fix the silica on treated surfaces but presents the drawback of forming on the treated surface a gelatinous deposit onto which also ambient dust has a tendency to adhere, which reduces its efficacy over time.
Patents WO 2005/025 317 and WO 2006/097 480 disclose various parasiticidal compositions in the form of aqueous suspensions based on an alkali metal bicarbonate, which have the advantage of not being toxic to man and animals. These compositions are applied by brushing or spraying onto the vertical surfaces of the buildings and equipment to be treated. The treatment of a livestock building, for example for rearing laying hens, after sanitary cleaning and mucking out, is usually performed by spraying with suspension. However, the operation requires specific low-pressure or high-pressure industrial spraying machines which represent a certain investment, and the operation requires several hours to apply the aqueous suspension to all the surfaces of the cages and those close to the feeding troughs. The drying of the aqueous suspensions is itself effective within a few minutes to a few hours depending on the applied thickness.
Patent WO 2006/097 504 discloses a parasiticidal composition in powder form based on an alkali metal bicarbonate, which may be applied by dusting onto the horizontal surfaces of buildings occupied by livestock on the ground. Here also, the treatment of ground surfaces requires several hours of work when large surfaces such as those of livestock buildings need to be treated, despite the use of specific equipment. Moreover, the floor is often made of slotted floorings or gratings, through which the animal droppings fall. When these slotted floorings are covered with product in powder form, the animals walking on these slotted floorings remove the product from the floor; this makes regular retreatment of these surfaces necessary.
The invention is directed towards providing an alternative disinfestation process that affords an appreciable saving both in application time and in investment on specific machines, which offers lasting efficacy in the control of parasites that develop on animals and in their environment.